1. Field of the Invention
The present invention relates to air conditioners and heat pumps having dual tangential blowers. More particularly, the field of the invention is that of pulley mounting and bearing systems for the tangential blowers of such air conditioners.
2. Description of the Related Art
Many known air conditioners may be installed in windows or other apertures of building walls in order to provide heating and/or cooling to the building interior. The air conditioners generally include both a conventional tangential blower for the indoor heat exchanger and an axial blower for the outdoor heat exchanger. The air conditioners also include some type of dividing wall which separates the indoor compartment of the unit from the outdoor compartment of the unit. Air is conventionally drawn into the unit through the sides, the rear, the outside, or the bottom of the unit and is blown out of the unit after passing over the heat exchangers.
One known type of air conditioner, termed a "packaged terminal" air conditioner or heat pump, is especially well adapted for use in light commercial and residential applications, e.g., hotel rooms or nursing homes. In those applications, both the non-obtrusive operation and ease of access and servicing of the air conditioner are important features; the hotel or nursing home owner generally desires an air conditioner which does not disturb the guests or residents and which may be quickly repaired so that the building space may be utilized for housing guests. Thus, the comfort of the resident is enhanced because of smooth and quiet running of the air conditioner, and the cost may be reduced through more efficient operation.
Such packaged terminal air conditioners may advantageously include tangential blowers for circulating air about the heat exchangers. Air conditioners which have tangential fans for moving air are much more quiet than conventional units because of the lower air velocity through the blowers and optimum spacing between the blower and the cut-off of the air conditioner. Furthermore, the induced air flow through the heat exchanger coils is much more uniform than in conventional units thereby causing substantially full utilization of the indoor and outdoor heat exchanger coils and providing greater efficiency of the appliance.
Further details of a packaged terminal air conditioner are disclosed in U.S. Pat. Nos. 5,094,089, entitled DRIVING SYSTEM FOR DUAL TANGENTIAL BLOWERS IN AN AIR CONDITIONER, No. 5,038,577, entitled AIR INTAKE ARRANGEMENT FOR AIR CONDITIONER WITH DUAL CROSS FLOW BLOWERS, No. 5,060,720, entitled METHOD AND APPARATUS FOR COOLING MOTORS OF CROSS FLOW BLOWERS, and No. 5,152,336, Ser. No. 07/654,305, filed on Feb. 12, 1991, entitled AIR CONDITIONER MODULAR UNIT WITH DUAL CROSS FLOW BLOWERS, all assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference.
In the aforementioned U.S. patents, a belt and pulley coupling is described that utilizes a single motor to directly drive one of the tangential blowers which then transmits motion via the belt and pulley coupling to the other tangential blower. The tangential blowers are disposed in an air handling housing which is separated into indoor and outdoor sections by a scroll shaped divider wall. The motor is disposed on the side of the air handling unit adjacent to the compressor while the coupling is mounted on an access cover on the other side of the air handling unit. By positioning the coupling away from the motor and compressor, the belt of the coupling is exposed to much less heat, moisture, and other by-products of the motor and compressor.
The tangential blower includes a pair of end discs which are attached by a plurality of blades. An axially disposed shaft is attached to the discs for mounting to the access cover of the air handling unit. The pulleys of the coupling include a hub portion which may be secured to the blower shaft by a set screw or the like. The shaft is mounted in a bearing located in the access cover to rotatably support the tangential blower. The forming of and steps necessary to assemble the multiplicity of parts complicates the manufacture of the air conditioner.
An undesirable consequence of this arrangement is that air is drawn through the small clearance between the blower shaft and the aperture in the access cover. This induced air stream is generally at a substantially different temperature than that in the interior of the air handler, and moisture often condenses within and on the bearing as the air traverses into the interior of the air handler. Because a substantial temperature difference may exist between the indoor compartment and the conditions exterior to the air handling unit, the bearing in the access cover may be subject to additional stress from temperature variation and performance deterioration due to moisture.
What is needed is an air conditioner which improves the blower coupling arrangement.
Also needed is an air conditioner which improves the blower mounting arrangement.
An additional need is for such an air conditioner which is simpler to manufacture.
A further need is for an air conditioner having a blower bearing removed from the access cover.